Here’s Why You Can’t Trust Your Memory

You may have heard that our memory works like a videocamera. You may have heard that our memory doesn’t work like a camcorder, in fact, unlike a computer or the information in our own DNA, our memories are stored with many alterations each time they are accessed. You may have heard that our memory doesn’t work like a camera, in fact, it works more like Chinese whispers, but what does this mean? [INTRO by Caro Waro & Cristina de Manuel] Perhaps we should start with… what is a memory? For you, it might be a sensory souvenir of a place or event in your mind’s eye, but what’s actually happening in your brain? Today I’m joined by Ali, Ali: Well, hello there! and we’re going to be talking to you about the unreliability of memory and the science of false memories. Ali: Oh yes we are… Ali: there are basically two types of memory – there’s your declarative, which is memories that you consciously recall, and non-declarative, like muscle memory – you don’t know how you ride a bike, you just can – and there are three ways we handle memories: we can encode them, we can consolidate them and we can retrieve them, and what is unsettling about these processes is that errors can occur in each of those steps, so without skipping to the beginning, do you remember what happened in the football clip at the start? Would your account be reliable? Inés: This is important because eye-witnesses and recall evidence are used all the time in medical and legal settings.

You may think you recall what happened, but do you actually? Would you be able to pick out the person who was whispering to the other in a line-up? Ali: Well… Hopefully you didn’t pick out anyone, because the person actually wasn’t in that clip. You may have got that, but you saw that clip less than two minutes ago. When it comes to recalling such a brief event, or even the face of a stranger who maybe you’ve seen briefly, it’s easy to misremember it, or perhaps even choose the person we felt fit the description best, even if they don’t entirely match.

And that has big implications for legal situations, such as line-ups of potential suspects. Inés: Indeed, the wording used when asking people to recall memories is very important too. In the clip we just saw I asked you to pick out a person, which may have led you to assume that they had to be there. Basically, words, your mood and other factors can suggest and alter memories. There was a study conducted by Loftus and Palmer where people were shown different videos of cars colliding at 20, 30 and 40 miles per hour, and when people were asked about how fast the cars were going upon colliding, they found their replies correlated better with the verb the researchers had used to describe the collision, such as bump, hit or smash, over the actual speed they witnessed in the video.

Ali: then they were asked if there was any broken glass – there wasn’t. But, those who had been primed by the word ‘SMASH’ were more likely to say that there was. The Loftus study showed that memory consistency is already pretty terrible within minutes of witnessing an event – so imagine the reliability of eyewitness testimony during a line-up weeks, or even months, after an event.

Inés: This applies even when you feel you remember something very vividly. “I remember it as if it were yesterday”. Ali: I do! I do! Inés: When a memory is formed at the same time or right before a strong emotional reaction, the memory formed can be stronger and this can make it seem more vivid. Most people will be able to tell you where they were and what they were doing when 9/11 happened, or some other notorious moment in their life, such as winning a prize, a first kiss or receiving awful news. Ali: however confidently we feel that we remember something doesn’t necessarily make that memory any more accurate, and what’s super-interesting is that people with fertile imaginations who love making stuff up, are more likely to introduce real errors into their memory at the encoding stage and create false memories.

Loftus – the smashy car researcher we spoke about earlier – also discovered that therapies (like hypnotherapy) which aim to uncover repressed memories by getting patients to imagine what might have happened, may instead be introducing false memories which are then “recalled” by the patient. Inés: So far, it seems like false memories are in fact, undesirable in spite of being an integral part of our existence. But, is there ever a reason to cause false memories on purpose? Ali: There is if you’re a man called Susumu Tonegawa Inés: Explain Ali: Susumu Tonegawa has spent the last 10 or so years trying to work out how a memory is built from the cells of our brains. Different groups of cells encode different memories and Tonegawa’s lab has used a funky technique called optogenetics to activate the cells storing a certain memory at will. The unfortunate subjects are mice. First they remember what the inside of a box looks like – then that memory can be activated by the researchers at the touch of a button.

And all this comes back to implanting false memories: if they activate the real memory and activate a fear-response at the same time then the mice end up with a new, false memory of the box being scary. Imagine if someone could make you think of your bedroom when you were a child and then forced you to think of a terrifying clown at same time. After a while you’d become afraid of that bedroom right? Inés: However, implanting false memories could be used on purpose for certain treatments.

One of the more controversial debates involves the implantation of false memories in the treatment of obesity, in which people seeking to lose weight could have false memories implanted that would make them more likely to avoid some foods whilst favouring others. There is also potential for false memory implantation to be used in the treatment of addiction and anxiety disorders such as PTSD and OCD, where strong memories and intrusive thoughts are brought up again and again without fading naturally over time.

False memories could change the emotions surrounding these experiences, allowing them to fade and become less vivid over time. So, there you go – the spooky truth about our unreliable mesh of memories! We really hope you enjoyed this video a big thank you to Ali and the YouTube Space, for making this happen Ali: Oh the YouTube Space, oh the YouTube Space Inés: The wonderful, shiny YouTube Space! Ali: Oh God it’s so shiny! So shiny that it’s matte black… Inés: And Ali runs a channel with Flo, our friend Flo called Collab Lab so we urge you to go check out an interview that we’ve done over there and subscribe to them because they’ve got some really exciting stuff coming up very soon that I can’t wait to see! So, as always, thank you so much for watching us and I will see you in the next one! Bye! [Music: Thastor & CryoSleepKitten] [Channel Art: Caro Waro & Cristina de Manuel] [Scripting, Hosting: Alistair Jennings & Inés Dawson] [Post-production: Inés Dawson] [Special Thanks to the YouTube Space] [Translated by {your name} into {language}]